Many mechanical power transmission devices are employed in environments where failure would be so critical, that redundant drive paths, that is, primary and secondary drive paths, are provided. A common example is in systems employed for changing the configuration of airfoils in aircraft such as flaps. Since proper control of an aircraft depends upon the ability to properly control the various airfoils that may be changed to change the aircraft configuration, it is absolutely necessary that control over the airfoils be maintained at all times. Conventionally, a primary load path is utilized to interconnect an actuator or drive for the airfoil with the airfoil itself. Additionally, a secondary path of power transmission to the airfoil from the drive is also provided. In the usual case, only the primary path is loaded during operation. Should it fail, then the loading is placed on the secondary path which allows control of the flaps until there is an opportunity to have the primary load path repaired.
Conventionally too, an indication of failure of the primary load path is provided upon the occurrence of such failure so as to alert appropriate personnel to the need for repair.
In airborne environments, it is, of course, highly desirable to minimize weight and volume of components, as well as to provide highly reliable systems.
The present invention is directed to accomplishing those goals.